Terminal side and base station side device, terminal device, base station, and wireless communication method

ABSTRACT

A terminal and base station side device, a terminal device, a base station, and a wireless communication method. The terminal side device includes a searching unit, configured to adopt a synchronization signal sequence corresponding to a target frequency range to be searched to search a target cell; and a synchronization unit, configured to perform synchronization based on the synchronization signal detected by the searching unit to synchronize the device to the target cell, the case the target frequency range belongs to a first frequency range, the searching unit adopts the synchronization signal sequence in a first subset of a synchronization signal sequence set to search the target cell, the first subset being a proper subset of the synchronization signal sequence set. Thereby, a number of synchronization signal sequence matching in a cell searching procedure is reduced and time for user equipment to synchronize to the target cell is shortened.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/553,439, filed Aug. 24, 2017, which is based on PCT filingPCT/CN2016/079241, filed Apr. 14, 2016, and claims priority to CN201510184481.0, filed Apr. 17, 2015, the entire contents of each areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure generally relates to the field of wirelesscommunication, and in particular to a device on a terminal side, aterminal device, a device on a base station side and a base station in awireless communication system, and wireless communication methodsapplied in the above devices.

BACKGROUND

With increasing requirements for high-speed data transmission, LTE(long-term evolution) becomes one of the most competitive wirelesstransmission technologies. A user equipment (UE) may access to an LTEnetwork only after a process including cell search, acquiring systeminformation of cell and random access. The major purpose of the cellsearch includes: (1) synchronizing with the cell in terms of frequencyand symbol; (2) acquiring system frame timing, i.e., a starting positionof a downlink frame; and (3) determining a physical layer cell identity(PCI) of the cell. The UE performs the cell search on start-up, however,in order to support the mobility, the UE may continuously search for aneighboring cell, perform synchronization and estimate the quality ofthe received signal for the neighboring cell, so as to determine whetherto perform handover or cell reselection.

With the increasing requirements for data transmission, a critical wayfor improving overall performance of the system is to increasetransmission bandwidth and improve spectrum utilization ratio. Underthis background, more and more operators focus on using unauthorizedfrequency bands, and consider taking the unauthorized frequency bands asa supplementary for existing LTE authorized frequency bands to improvequality of service for users.

Communication on the unauthorized frequency band for a cell andcommunication for other systems co-exist and share the frequencyspectrum resource. Therefore, to a certain extent, the signal of thecell must retreat due to other systems having a higher priority (such asradar), or the cell may operate in a fixed time period after negotiatingwith other systems (such as WiFi). If the cell search andsynchronization take a long time, it is not beneficial for initialaccess of the UE, cell reselection and handover, which results inlimitation for the usage of the unauthorized frequency band. Therefore,it is desired that the UE can perform search and synchronize rapidlywith respect to a cell on the unauthorized frequency band.

SUMMARY

An overview of the present disclosure is simply given below to providebasic understanding for some aspects of the present disclosure. Itshould be understood that this overview is not an exhaustive overview ofthe present disclosure. It is intended to neither determine a criticalpart or an important part of the present disclosure, nor to limit thescope of the present disclosure. An object of the overview is only togive some concepts in a simplified manner, which serves as a preface ofa more detailed description described later.

A device on a terminal side in a wireless communication system isprovided according to an aspect of the present disclosure. The deviceincludes: a searching unit configured to search for a target cell bymeans of a synchronization signal sequence corresponding to a targetfrequency range to be searched; and a synchronizing unit configured toperform synchronization based on a synchronization signal detected bythe searching unit, so as to synchronize the device with the targetcell, where in a case that the target frequency range falls within afirst frequency range, the searching unit searches for the target cellby means of a synchronization signal sequence in a first subset of asynchronization signal sequence set, and the first subset is a propersubset of the synchronization signal sequence set.

A wireless communication method performed by a device on a terminal sideis provided according to another aspect of the present disclosure. Themethod includes: searching for a target cell by means of asynchronization signal sequence corresponding to a target frequencyrange to be searched; and performing synchronization based on a searchedsynchronization signal, so as to synchronize the device with the targetcell, where in a case that the target frequency range falls within afirst frequency range, the target cell is searched by means of asynchronization signal sequence in a first subset of a synchronizationsignal sequence set, and the first subset is a proper subset of thesynchronization signal sequences set.

A device on a base station side in a wireless communication system isprovided according to another aspect of the present disclosure. Thedevice includes: an identity group determining unit configured todetermine a physical layer cell identity group for a target cell, wherethe physical layer cell identity group is related to a frequency rangeof the target cell; and a secondary synchronization signal sequencegenerating unit configured to generate a secondary synchronizationsignal sequence for a secondary synchronization signal of the targetcell based on the physical layer cell identity group, where in a casethat the frequency range of the target cell falls within a firstfrequency range, the physical layer cell identity group is a firstsubset of a physical layer cell identity group set, and the first subsetis a proper subset of the physical layer cell identity group set.

A wireless communication method performed by a device on a base stationside is provided according to an aspect of the present disclosure. Themethod includes: determining a physical layer cell identity group for atarget cell, where the physical layer cell identity group is related toa frequency range for the target cell; and generating a secondarysynchronization signal sequence for a secondary synchronization signalof the target cell based on the physical layer cell identity group,where in a case that the frequency range of the target cell falls withina first frequency range, the physical layer cell identity group is afirst subset of a physical layer cell identity group set, and the firstsubset is a proper subset of the physical layer cell identity groupsset.

A terminal device capable of communicating with a base station on afirst carrier is provided according to an aspect of the presentdisclosure. The device includes: a communication unit configured toreceive a synchronization signal transmitted from the base station on asecond carrier different from the first carrier; and a synchronizingunit configured to match a secondary synchronization signal in thesynchronization signal with a sequence in a first subset of a secondarysynchronization signal sequence set, to determine the secondarysynchronization signal, and the first subset is a proper subset of thesecondary synchronization signal sequences set.

A base station in a wireless communication system is provided accordingto an aspect of the present disclosure, and the base station is capableof communicating with a wireless communication terminal on a firstcarrier. The base station includes a communication unit configured totransmit a synchronization signal comprising a secondary synchronizationsignal on a second carrier different from the first carrier, wherein thesecondary synchronization signal is selected from a first subset of asecondary synchronization signal sequence set, and the first subset is aproper subset of the secondary synchronization signal sequence set.

According to the aspects of the present disclosure, the number ofmatching with the synchronization signal sequence during cell search isreduced, thereby greatly shortening a time period for synchronizing theUE to the target cell.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the present disclosure are described below inconjunction with the drawings, hence the above and other objectives,features and advantages of the present disclosure can be understood moreeasily. In the drawings, same or corresponding technical features orcomponents may be represented with same or corresponding referencenumerals. The size and relative position of a unit are unnecessarilydrawn to scale in the drawings.

FIG. 1 is a structural block diagram of a device on a terminal side in awireless communication system according to an embodiment of the presentdisclosure;

FIG. 2 is a structural block diagram of a device on a terminal side in awireless communication system according to another embodiment of thepresent disclosure;

FIG. 3 is a flowchart of a wireless communication method applied in adevice on a terminal side according to an embodiment of the presentdisclosure;

FIG. 4 is a structural block diagram of a device on a base station sidein a wireless communication system according to an embodiment of thepresent disclosure;

FIG. 5 is a structural block diagram of a device on a base station sidein a wireless communication system according to an embodiment of thepresent disclosure;

FIG. 6 is a flowchart of a wireless communication method applied in adevice on a base station side according to an embodiment of the presentdisclosure;

FIG. 7 is a structural block diagram of a wireless terminal deviceaccording to an embodiment of the present disclosure;

FIG. 8 is a timing diagram illustrating a synchronization process in awireless communication system according to an embodiment of the presentdisclosure;

FIG. 9 is a timing diagram illustrating a synchronization process in awireless communication system according to another embodiment of thepresent disclosure;

FIG. 10 is a block diagram illustrating an exemplary structure of acomputer capable of implementing the present disclosure;

FIG. 11 is a block diagram illustrating a first example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure can be applied;

FIG. 12 is a block diagram illustrating a second example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure can be applied;

FIG. 13 is a block diagram illustrating a schematic configuration of asmart phone to which the technology according to the present disclosurecan be applied.

DETAILED DESCRIPTION OF EMBODIMENTS

An exemplary embodiment of the present invention will be describedhereinafter in conjunction with the drawings. For the purpose ofconciseness and clarity, not all features of the embodiments aredescribed in this specification. However, it should be understood thatmultiple decisions specific to the embodiment have to be made in aprocess of developing any such embodiment to realize a particular objectof a developer, for example, conforming to those constraints related toa system and a business, and these constraints may change as theembodiments differs. Furthermore, it should also be understood thatalthough the development work may be very complicated andtime-consuming, for those skilled in the art benefiting from the presentdisclosure, such development work is only a routine task.

Here, it should also be noted that in order to avoid obscuring thepresent disclosure due to unnecessary details, only a device structureand/or processing steps closely related to the solution according to thepresent disclosure are illustrated in the drawing, and other detailshaving little relationship to the present disclosure are omitted.

In order to support cell search, two types of downlink synchronizationsignals are defined in the LTE: 3 primary synchronization signals (PSS)and 168 secondary synchronization signals (SSS). In this case, 504different PCIs are defined by combinations of the primarysynchronization signals and the secondary synchronization signals in theLTE, and each of the PCIs corresponds to a specific downlink referencesignal sequence. The 168 secondary synchronization signals arerespectively identified as 168 cell identity groups, and the 3 primarysynchronization signals are respectively identified as 3 cellidentities. The PCI of the cell is determined based on both the primarysynchronization signal and the secondary synchronization signal. A basestation determines a transmission sequence of the transmitted primarysynchronization signal and the transmitted secondary synchronizationsignal once determining the cell identity group and the cell identity(PCI=3*cell identity group+cell identity). After finding the signals, aUE may demodulate the signals based on all possible combinations, todetermine the cell identity group and the cell identity used by the basestation.

In order to demodulate the PCI of the cell, the UE matches possibleprimary synchronization signals and secondary synchronization signalsone by one. In order to improve a speed of synchronizing the UE to thecell and to shorten an access time, a new technical solution is providedin the present disclosure, in which, a target cell is searched for usinga synchronization signal sequence in a specific proper subset of asynchronization signal sequence set defined in an existing communicationprotocol, to shorten a possible access time for a UE. For example, thespecific proper subset may be determined based on a target frequencyrange to be searched.

FIG. 1 is a structural block diagram of a device 100 on a terminal sidein a wireless communication system according to an embodiment of thepresent disclosure. For example, the device 100 for example but is notlimited to a mobile terminal device such as a mobile phone and anotebook computer, and a component (such as a chip) or means which arearranged in the mobile terminal device or are used in combination withthe mobile terminal.

The device 100 includes a searching unit 101 and a synchronizing unit102. The searching unit 101 is configured to search for a target cellwith a synchronization signal sequence corresponding to a targetfrequency range to be searched. For example, in a case that the targetfrequency range falls within a first frequency range, the searching unit101 may search for the target cell with a synchronization signalsequence in a first subset, corresponding to the first frequency range,of a synchronization signal sequence set. Here, the first subset is aproper subset of the synchronization signal sequence set. Thesynchronization signal sequence set for example but is not limited to asynchronization signal sequence set defined in an existing communicationprotocol. A correspondence between the target frequency range and thefirst subset may be preset, and may be preset in a UE (for example, thecorrespondence may be written in a boot file of the UE) or informed tothe UE by a base station. In an embodiment, the device 100 may furtherinclude a determining unit (not shown) configured to determine whetherthe target frequency range falls within the first frequency range.

In an embodiment, the first frequency range may be a range on theunauthorized frequency band for a wireless communication system, and thetarget cell to be searched is a cell which may be accessed on theunauthorized frequency spectrum. In the embodiment, a synchronizationsignal sequence set is for example and not limited to a synchronizationsignal sequence set used when a communication device in the wirelesscommunication system communicates on a carrier in an authorizedfrequency band. Since the wireless communication system where the device100 is located typically can only perform opportunistic use onunauthorized frequency band resources in which an idle resource may befleet, the solution according to the present disclosure is particularlyadapted to search for a cell operating in an unauthorized frequencyband, thereby shortening a time period for searching for a cell andimproving a resource utilization rate. Optionally, for example, theunauthorized frequency band may be further divided into multiple subfrequency ranges, such as a sub frequency range co-existing with theWiFi/Radar and a common unauthorized sub frequency range. The firstfrequency range may correspond to one of the multiple sub frequencyranges. For example, the synchronization signal sequence set is asynchronization signal sequence set in the whole unauthorized frequencyband, and fast search is performed with a synchronization signalsequence contained in a proper subset of the synchronization signalsequence set. A requirement on an access time for a sub frequency rangeco-existing with a different system is stricter than that for a commonsub frequency range. In this example, a proper subset of thesynchronization signal sequence corresponding to the sub frequency rangeco-existing with the different system may be set to have a smaller rangethan the common unauthorized frequency range, thereby furtheraccelerating a process of cell discovery.

The synchronizing unit 102 is configured to perform synchronizationbased on a synchronization signal detected by the searching unit 101, tosynchronize the device 100 to the target cell. Due to the usage of theproper subset, the number of matching possibly performed when the UEsearches for the target cell is reduced significantly, and a time periodfor synchronization between the UE and the target cell is furthershortened.

Hereinafter, for simple description, a devices and a method according tothe present disclosure are described in conjunction with access into acell in an unauthorized frequency band in a way of example. It can beunderstood by those skilled in the art that, the device and methodaccording to the present disclosure are also adapted to access into anyother cells such as an authorized frequency range in which asynchronization process needs to be accelerated, and also thesynchronization time can be shortened. For example, in a scenario ofdense deployment of small cells, a UE moving at a high speed also needsto access into the small cell rapidly. Therefore, a frequency range ofthe small cell may be taken as the first frequency range, so as toaccelerate a synchronization process.

For the synchronization signals currently defined, the number ofmatching with the primary synchronization signals is 3 at most sincethere are three primary synchronization signals, and the number ofmatching with the secondary synchronization signals is up to 168 sincethe secondary synchronization signal has different sequences indifferent frames and there are 168 secondary synchronization signals.Accordingly, in a solution in which a proper subset of a synchronizationsignal sequence set is taken as a candidate synchronization signal setto be matched, the secondary synchronization signals can be optimizedgreatly. Therefore, in an embodiment, the synchronization signalsequence described above may be a secondary synchronization signalsequence. The searching unit 101 may be configured to decode a secondarysynchronization signal of the target cell with a secondarysynchronization signal sequence corresponding to, for example, a targetfrequency range in the unauthorized frequency band.

Currently, there is an agreement in the industry for utilization of theunauthorized frequency band that the unauthorized frequency band is usedwith assistance of the authorized frequency band, that is, a LicenseAssisted Access of LTE (LAA-LTE) is used in a carrier aggregation way.For an LAA-LTE cell, in an embodiment, it may be defined that asecondary synchronization signal only uses a certain subset in anexisting standard. For example, only 56 base sequences of 168 basesequences are used. In this case, the number of self-correlation(matching) performed by an UE on the secondary signal sequence isreduced, thereby greatly shortening the synchronization time.

In an embodiment, the device 100 may further include a communicationinterface (not shown). The communication interface may be configured toacquire a command for searching for the target cell and indicationinformation of a first subset through a first cell in the authorizedfrequency band. For example, the communication interface may beconfigured to receive signaling including the command for searching forthe target cell and the indication information of the first subsetthrough the first cell in the authorized frequency band. The signaling,for example, may be broadcast signaling or RRC signaling.

By taking a case that the target cell is searched for by taking a propersubset, corresponding to the unauthorized frequency band, of thesecondary synchronization signal sequence set as a synchronizationsignal sequence in the LAA-LTE scenario as an example, base sequences(there are 168 base sequences in the existing standard) of the secondarysynchronization signal may be grouped based on a value of PCI mod 6, togroup the sequences used by the secondary synchronization signal into 6subsets as candidates of the first subset, and each of the subsets isnumbered and the number is taken as indication information of the firstsubset. In another example, the subsets may be grouped based on an orderof group IDs. For example, the base sequence of the secondarysynchronization signal is grouped into 3 subsets.

In for example the above LAA-LTE scenario, after the device 100 accessesinto the target cell, the communication interface of the device 100 maybe further configured to acquire an indication related to an updatedsynchronization signal sequence through the target cell. In for examplea scenario of communication in the unauthorized frequency band withoutassistance of an authorized carrier, the communication interface of thedevice 100 may also be configured to acquire an indication related to anupdated synchronization signal sequence through the target cell afterthe device 100 accesses into the target cell. In other words, theindication related to the updated synchronization signal sequence canalso be acquired in the unauthorized frequency band in this example.

FIG. 2 is a structural block diagram of a device 200 on a terminal sidein a wireless communication system according another embodiment of thepresent disclosure. The device 200 may include a searching unit 201, asynchronizing unit 202, a detecting unit 203 and a notifying unit 204.Functions and structures of the searching unit 201 and synchronizingunit 202 the same as those of the searching unit 101 and synchronizingunit 102 described in conjunction with FIG. 1 are not repeated herein.In the embodiment and other embodiments below, a same term (such as“first subset” and “first frequency range”) represents same meaning asit does in the aforementioned embodiment.

The detecting unit 203 may detect whether an interference to a referencesignal received by the device 200 in a first frequency range is toolarge due to using the first subset. Whether the interference is toolarge by for example but not limited to detecting a signal of referencesignal received quality (RSRQ) and the like. For example but not limitedto, in a case that it is determined there is a strong interference bydetecting the RSRQ, a time duration of the strong interference may befurther determined. It may be determined that the interference to thereference signal received by the device 200 in the first frequency rangeis too large due to using the first subset, in a case that the timeduration of the strong interference exceeds a predetermined timethreshold. In a case that it is detected that the interference is toolarge, the notifying unit 204 may notify a base station in a servingcell of the device 200 or a target cell of a result of the detecting. Itshould be noted that, in some examples, a current serving cell (such asa serving cell in an authorized frequency band) of the device 200 sharesa base station with the target cell in an unauthorized frequency band.In other examples, the serving cell and the target cell may be managedby different base station entities. In this case, the notifying unit 204may notify a base station in the serving cell of the a result of thedetecting, and then the base station in the serving cell transmits theresult of the detecting to a base station in the target cell through X2signaling. In yet another embodiments, the device 200 may directlyreport the result of the detecting to the base station in the targetcell after accessing into the target cell.

A synchronization signal sequence set may include multiple propersubsets for cell search in the first frequency range. The searching unit201 may detect a synchronization signal transmitted by the base stationof the target cell and an indication of a second subset selected fromthe multiple proper subsets by the base station of the serving cell/thetarget cell in response to the notification that the interference is toolarge sent by the notifying unit 204. Needless to say, the selectedsecond subset is different from the first subset. The searching unit 201may decode the transmitted synchronization signal with the second subsetin response to the indication of the second subset.

Optionally, the base station of the target cell may select anothersynchronization signal sequence from the first subset in response to thenotification that the interference is the too large sent by thenotifying unit 204, instead of selecting a subset.

In the LAA-LTE scenario, a target cell of LAA-LTE is generally deployedin a frequency band different from a macro cell and a small cell, henceit is very possible to use same PSS and SSS in an actual deployment.Therefore, in a case of synchronizing to an LAA-LTE cell, in order todetermine a usage sequence of a PSS or SSS used in the LAA-LTE cell,sequences of the macro cell and the small cell may be firstly used formatching, so as to accelerating a synchronization speed as much aspossible. As an example, in a case that the device 200 accesses into anunauthorized frequency spectrum with assistance of LTE, the searchingunit 201 searches by firstly taking a secondary synchronization signalof a cell in which the device 200 previously resides as asynchronization signal sequence. It can be understood that, thesynchronization signal sequence contained in the first subset maycorrespond to a synchronization signal sequence of a serving cell in acurrent authorized frequency band or a previous authorized frequencyband. The technical content and technical content to be described beloware also applicable to the device 100 described in conjunction with FIG.1.

In the case that the device 200 needs to perform inter-cell handover,the searching unit 201 may acquire an indication related to the firstsubset based on radio resource control (RRC) configuration informationof a base station currently serving the device 200. The synchronizationsignal sequence set may include multiple proper subsets for cell searchin the first frequency range, and a sequence number of the first subsetis included in RRC configuration information.

If the searching unit 201 cannot search out the target cell with allsequences in the first subset, the searching unit 201 may search with asequence in a third subset. The third subset here is one of the multipleproper subsets for the cell search in the first frequency range and isdifferent from the first subset.

FIG. 3 is a flowchart illustrating a wireless communication methodapplied in a device on a terminal side according to an embodiment of thepresent disclosure. In step S301, a target cell is searched for with asynchronization signal sequence corresponding to a target frequencyrange to be searched. For example, in a case that the target frequencyrange falls within a first frequency range, the target cell is searchedfor with a synchronization signal sequence in a first subset of asynchronization signal sequence set. Here, the first subset is a propersubset of the synchronization signal sequence set. In step S302,synchronization is performed based on the found synchronization signal,to synchronize the device to the target cell. The embodiments andvariations related to the steps in FIG. 3 are the same as thosedescribed in conjunction with FIGS. 1 and 2, which are not describedhereinafter anymore.

A device 400 on a base station side in the wireless communication systemaccording to an embodiment of the present disclosure is described belowin conjunction with FIG. 4. The device 400 includes an identity groupdetermining unit 401 and a secondary synchronization signal sequencegenerating unit 402. The identity group determining unit 401 may beconfigured to determine a physical layer cell identity group of a targetcell. The identity group determining unit 401 may be configured todetermine the physical layer cell identity group based on a frequencyrange of the target cell. For example, in a case that the frequencyrange of the target cell falls within a first frequency range, thephysical layer cell identity group is determined as a first subset whichis a proper subset of the physical layer cell identity group set. In anexample, the identity group determining unit 401 may autonomouslydetermine the physical layer cell identity group of the target cellbased on the frequency range of the target cell. Optionally, theidentity group determining unit 401 may determine the physical layercell identity group of the target cell based on the frequency range ofthe target cell according to configuration made by an operator throughoperation administration and maintenance (OAM). In an example, thedevice 400 may further include a determining unit configured todetermine whether the frequency range of the target cell falls withinthe first frequency range.

The secondary synchronization signal sequence generating unit 402 isconfigured to generate a secondary synchronization signal sequence for asecondary synchronization signal of the target cell based on thephysical layer cell identity group determined by the identity groupdetermining unit 400. In an embodiment, a secondary synchronizationsignal SSS may include a Zadoff-Chu sequence with a length of 63 (adirect current subcarrier (DC subcarrier) is arranged in the middle ofthe sequence, hence an actual transmission length is 62) and 5subcarriers additionally reserved for a protection frequency band at aboundary, to form an SSS occupying 72 subcarriers (not including the DC)at the center. The SSS is transmitted in subframes 0 and 5 regardless offrequency division multiplexing (FDM) or time division multiplexing(TDM). In the LTE, the SSS is designed specially. For example, values oftwo SSSes (SSS1 and SSS2 are located in subframes 0 and 5, respectively)are selected from a set including 168 optional values, for example, aproper subset including 56 elements (referring to table 6.11.2.1-1 ofstandard 36.211, N_(ID) ^((I))=N_(ID) ^(cell)/3). A value of SSS₁ isdifferent from that of SSS2, therefore, a UE can be allowed to detect atiming of 10 ms for a system frame (i.e., the location of the subframe0) once receiving only one SSS. This is because, during the cell search,the UE may search for multiple cells, and a time window of the searchmay be not enough for the UE to detect more than one SSS.

In an embodiment, the first frequency range may be a range on theunauthorized frequency band for the wireless communication system. Thetarget cell may be a cell which may be accessed on the unauthorizedfrequency spectrum. In practice, the first frequency range may be otherfrequency ranges in which a synchronization process needs to beaccelerated. For example, in a scenario of dense deployment of the smallcells, if a UE moves at a high speed, the UE needs to access into thesmall cell rapidly. In this case, a frequency range for the small cellmay be taken as the first frequency range, to accelerate thesynchronization process.

FIG. 5 is a structural block diagram of a device 500 on a base stationside in a wireless communication system according to an embodiment ofthe present disclosure. The device 500 includes an identity groupdetermining unit 501, a secondary synchronization signal sequencegenerating unit 502, a communication unit 503 and an informationupdating unit 504. functions and structures of the identity groupdetermining unit 501 and the secondary synchronization signal sequencegenerating unit 502 same as those of the identity group determining unit401 and secondary synchronization signal sequence generating unit 402described in conjunction with FIG. 4 are not described hereinafteranymore.

In the embodiment that the first frequency range is a range on theunauthorized frequency band for the wireless communication system andthe target cell is a cell which may be accessed on the unauthorizedfrequency spectrum, the device 500 may transmit a secondarysynchronization signal in an unauthorized frequency band correspondingto the target cell via the communication unit 503.

In addition, in an example, when a device on a UE side detects that aninterference to a reference signal received by the device on the UE sidein the first frequency range is too large due to using the first subsetand notifies the base station of the target cell of a result of thedetecting indicating that the interference is too large, thecommunication unit 503 of the device 500 of the base station side mayfurther receive the notification indicating that the interference istoo-large. It should be noted that, in some examples, a current servingcell (for example a serving cell in an authorized frequency band) of thedevice on the UE side shares a base station with a target cell in anunauthorized frequency band. In other examples, the serving cell and thetarget cell may be managed by different base station entities. In thiscase, the result of the detecting may be notified to a base station ofthe serving cell, and then the base station of the serving celltransmits the result of the detecting to a base station of the targetcell through X2 signaling. In yet another embodiments, the device on theUE side may directly report the result of the detecting to the basestation of the target cell after accessing into the target cell. In acase that the notification is received by the communication unit 503,the identity group determining unit 501 may determine a second subset asa physical layer cell identity group, the second subset is a propersubset of the physical layer cell identity group set and is differentfrom the first subset. Then, the secondary synchronization signalsequence generating unit 502 may regenerate a secondary synchronizationsignal sequence based on the second subset. In a case that the identitygroup determining unit 501 determines the second subset as the physicallayer cell identity group, the information updating unit 504 maygenerate system broadcast information, including indication informationrelated to the second subset, to be transmitted by the target cell.Optionally, the information updating unit 403 may generate systembroadcast information, including indication information related to thesecond subset, to be transmitted in an authorized frequency band.

In another example, the communication unit 503 may notify other deviceson the base station side in the wireless communication system such as adevice on a neighboring base station side of the indication informationrelated to the second subset. The example is described hereinafter.

In an embodiment, the device 400 (500) on the base station side mayacquire a physical layer cell identity group subset of a neighboringcell of the target cell, and in the case that radio resource managementrelated to the neighboring cell is performed on a device on a terminalside in a current cell, generate radio resource control signaling, tonotify the device on the terminal side of the identity group subset ofthe neighboring cell.

In another embodiment, the communication unit of the device 400 (500) onbase station side may report an event that the interference is too largeto a core network via an S1 interface on receiving the notification thatthe interference is too large and acquire information on an updated cellidentity group from the core network.

FIG. 6 is a flowchart illustrating a wireless communication methodapplied in a device on a base station side according to an embodiment ofthe present disclosure. In step S601, a physical layer cell identitygroup of a target cell is determined. The physical layer cell identitygroup is related to a frequency range of the target cell. For example,in a case that the frequency range of the target cell falls within afirst frequency range, the physical layer cell identity group is a firstsubset of a physical layer cell identity group set, and the first subsetis a proper subset of the physical layer cell identity group set. Instep S602, a secondary synchronization signal sequence for a secondarysynchronization signal of the target cell is generated based on thephysical layer cell identity group. The embodiments and variationsrelated to the steps in FIG. 6 are the same as those described inconjunction with FIGS. 4 and 5, and are not described hereinafteranymore.

FIG. 7 is a structural block diagram of a wireless terminal device 700according to an embodiment of the present disclosure. The wirelessterminal device 700 can communicate with a base station on a firstcarrier. In an example, the first carrier may be in an authorizedfrequency band. The wireless terminal device 700 may include acommunication unit 701 and a synchronizing unit 702. The communicationunit 701 may receive a synchronization signal sent from the base stationon a second carrier different from the first carrier. In an example, thesecond carrier may be in an unauthorized frequency band. Thesynchronizing unit 702 may match a secondary synchronization signal inthe synchronization signal with a sequence in a first subset of asecondary synchronization signal sequence set, to determine thesecondary synchronization signal. Here, the first subset is a propersubset of the secondary synchronization signal sequence set. In anembodiment, the secondary synchronization signal sequence set may beused when the wireless terminal device communicates on the firstcarrier.

A base station in the wireless communication system is further providedaccording to an embodiment of the present disclosure. The base stationcan communicate with a wireless communication terminal on a firstcarrier. The base station includes a communication unit. thecommunication unit may be configured to transmit a synchronizationsignal including a secondary synchronization signal on a second carrierdifferent from the first carrier. Here, a secondary synchronizationsignal may be selected from a first subset which is a proper subset of asecondary synchronization signal sequence set. In an embodiment, thefirst carrier may be a carrier signal in authorized frequency band andthe second carrier may be a carrier signal on an unauthorized frequencyband. The secondary signal sequence set may be, for example, used whenthe base station communicates on the first carrier.

Hereinafter, the embodiments of the present disclosure are described inconjunction with FIGS. 8 and 9. It should be noted that, although ascenario of unauthorized frequency spectrum access with assistance ofthe LTE is taken as an example in FIGS. 8 and 9, those skilled in theart can apply corresponding solutions in an independent unauthorizednetwork (i.e., a network without assistance of LTE) with conventionallabors.

FIG. 8 is a timing diagram illustrating a synchronization process in awireless communication system according to an embodiment of the presentdisclosure. FIG. 8 shows a scenario of an unauthorized frequencyspectrum access with assistance of LTE. In the embodiment, all of cellsand all of user equipments use a same fixed subset of a synchronizationsignal sequence set as a first subset. At a time instant T81, a UEcommunicates with a base station on a primary component carrier (anauthorized frequency band in the embodiment). At a time instant T82, thebase station transmits on the primary component carrier, a commandindicating the UE to handover onto a secondary component carrier (anunauthorized frequency band in the embodiment) for communication to theUE. At a time instant T83, the UE switches to receive broadcastinformation on the secondary component carrier in response to thecommand. The broadcast information carries the fixed subset, as thefirst subset, of the synchronization signal sequence set. At a timeinstant T84, the UE matches a synchronization signal sequence in thereceived broadcast information with, for example, a fixed subsetprestored in a boot file. Since the fixed subset is matched with thesynchronization signal sequence, a secondary synchronization signal, aprimary synchronization signal and a physical identity of a cellaccessed in the unauthorized frequency band are determined. In thiscase, at a time instant T85, the UE is synchronized to the celloperating in the unauthorized frequency band and perform normalcommunication with the cell. In the embodiment, since the secondarycells uses the fixed subset of the synchronization signal sequence set,a serving base station operating in the unauthorized frequency band doesnot need to notify other base stations of the subset.

Reference is still made to FIG. 8, as compared with the scenario thatall of the cells and all of the user equipments use the same fixedsubset of the synchronization signal sequence set as the first subset,alternatively, each of the cells may use a fixed subset corresponding tothe cell. In this case, at the time instant T84, the UE firstly matchesthe synchronization signal sequence in the broadcast information with adefault subset. In the case that the synchronization signal sequence ismatched with the default subset unsuccessfully, the UE may serve anothersubset as the default set with another subset, to match with thesynchronization signal sequence. In an example, the UE may firstly servea primary synchronization signal and a secondary synchronization signalsame as those in the previous communication on the primary componentcarrier as the default subset, to match with the synchronization signalset.

FIG. 9 is a timing diagram illustrating a synchronization process in awireless communication system according to another embodiment of thepresent disclosure. FIG. 9 shows a scenario of an unauthorized frequencyspectrum access with assistance of the LTE. In the embodiment, all ofthe cells use a default subset of a synchronization signal sequence setas a first subset first. At a time instant T91, a UE communicates with aserving base station on a primary component carrier (an authorizedfrequency band in the embodiment). At a time instant T92, the basestation transmits on the primary component carrier, a command indicatingthe UE to handover onto a secondary component carrier (an unauthorizedfrequency band in the embodiment) for communication to the UE. At a timeinstant T93, the UE switches to receive broadcast information on thesecondary component carrier in response to the command. The broadcastinformation carries a fixed subset, which is the first subset, of thesynchronization signal sequence set. At a time instant T94, the UEmatches a synchronization signal sequence in the received broadcastinformation with, for example, a default subset (preferably, a subsetsame as a default subset of a cell) prestored in a boot file. At a timeinstant T95, the UE is synchronized to a cell operating in theunauthorized frequency band and then performs normal communication withthe cell.

At a time instant T96, the UE detects whether an interference to anreference signal received in the unauthorized frequency band by the UEis too large due to using the proper subset of the synchronizationsignal sequence set. If the interference is too large, the UE notifiesthe base station of the cell of the result of the detecting indicatingthat the interference is too large at a time instant 97. Thenotification may optionally be transmitted on the primary componentcarrier (the authorized frequency band) or the secondary componentcarrier (the unauthorized frequency band). At a time instant T98, thebase station replaces the proper subset with another proper subset orselects a signal sequence (such as a secondary synchronization signalsequence) based on the original subset, on receiving the notification.Then, at time instants T99 and T910, the selected subset or the selectedsequence are respectively transmitted to the UE and other base stations.Here, T99 and T910 may be the same time instant or different timeinstants.

The present disclosure is described above by referring to the flowchartsand/or the block diagrams of the methods and the devices according tothe present disclosure. Each block of the flowcharts and/or the blockdiagrams and a combination of blocks of the flowcharts and/or the blockdiagrams can be implemented with computer program instructions. Thesecomputer program instructions may be provided to a general-purposecomputer, a special-purpose computer or processors of other programmabledata processing devices, to produce a machine, so as to generate adevice implementing functions/operations defined in the blocks of theflowcharts and/or the block diagrams by executing these instructions viaa computer or other programmable data processing devices.

These computer program instructions may also be stored in a computerreadable medium capable of instructing the computer or otherprogrammable data processing devices to operate in a specific manner. Inthis way, a manufacture including an instruction means (instructionmeans) implementing the functions/operations defined in the blocks ofthe flowchart and/or the block diagram is produced with the instructionstored in the computer readable medium.

The computer program instructions may also be loaded to the computer orother programmable data processing devices, in this way, a series ofoperation steps are performed on the computer and other programmabledata processing devices, to generate a process realized by the computer.Therefore, the instructions executed on the computer or otherprogrammable devices provide a process of implementing thefunctions/operations defined in the blocks of the flowcharts and/or theblock diagrams.

It should be noted that, the flowchart and the block diagram in thedrawings illustrate architectures, functions and operations which may beimplemented based on the systems, methods and computer program productsaccording to the embodiments of the present disclosure. Regarding onthis, each block of the flowchart or the block diagram can represent amodule, a program segment or a portion of codes. The module, the programsegment or the portion of codes contain one or more executableinstructions for implementing defined logical functions. It should bealso noted that, in some alternative implementations, the functionsshown in the blocks may be performed in an order different from theorder shown in the drawings. For example, functions in two blocksrepresented successively may be performed in parallel, or sometimesperformed in an order reverse to the order shown in the drawings, whichdepends on the related functions. It should be noted that, each block ofthe block diagrams and/or the flowcharts and a combination of blocks ofthe block diagram and/or the flowchart may be implemented by a dedicatedhardware-based system performing specified functions or operations, ormay be implemented by a combination of dedicated hardware and computerinstructions.

FIG. 10 is a block diagram illustrating an exemplary structure of acomputer capable of implementing the present disclosure. In FIG. 10, acentral processing unit (CPU) 1001 executes various processing accordingto a program stored in a read-only memory (ROM) 1002 or a program loadedto a random access memory (RAM) 1003 from a memory section 1008. Thedata needed for the various processing of the CPU 1001 may be stored inthe RAM 1003 as needed.

The CPU 1001, the ROM 1002 and the RAM 1003 are linked with each othervia a bus 1004. An input/output interface 1005 is also linked to the bus1004.

The following components are linked to the input/output interface 1005:an input section 1006 including a keyboard, a mouse and the like, anoutput section 1007 including a display such as a cathode ray tube(CRT), a liquid crystal display (LCD), a speaker and the like, a memorysection 1008 including hard disc and the like, and a communicationsection 1009 including a network interface card such as a LAN card, amodem and the like. The communication section 1009 performscommunication processing via a network such as the Internet.

A driver 1010 may also be linked to the input/output interface 1005, ifneeded. If needed, a removable medium 1011, for example, a magneticdisc, an optical disc, a magnetic optical disc, a semiconductor memoryand the like, may be installed in the driver 1010, so that the computerprogram read therefrom is installed in the memory section 1008 asappropriate.

In a case where the foregoing steps and processing is achieved throughsoftware, programs forming the software are installed from a networksuch as the Internet or a memory medium such as the removable medium1011.

It should be appreciated by those skilled in the art that the memorymedium is not limited to the removable medium 1011 shown in FIG. 10,which has program stored therein and is distributed separately from themethod so as to provide the programs to users. The removable medium 1011may be, for example, a magnetic disc, a compact disc (including compactdisc read-only memory (CD-ROM) and digital versatile disc (DVD), amagneto optical disc (including mini disc (MD)), and a semiconductormemory. Alternatively, the memory medium may be the hard discs includedin ROM 1002 and the memory section 1008 in which programs are stored,and can be distributed to users along with the device in which they areincorporated.

The base station according to the present disclosure, for example, canbe implemented as any types of evolved node B (eNB), such as a macro eNBand a small eNB. The small eNB may be an eNB of a cell having a smallercoverage range than a macro cell, such as a pico-cell eNB, a micro eNBand a family (femto-cell) eNB. Alternatively, the base station may alsobe implemented as any types of base stations, such as a NodeB and a basetransceiver station (BTS). The base station may include an entity (alsoreferred to a base station device) configured to control wirelesscommunication; and one or more remote radio heads (RRHs) arranged in aposition different from the entity. With the development of C-RAN(Centralized, Cooperative, Cloud RAN), the above entity controlling thewireless communication may be also a baseband cloud processing devicesuch as a server. In addition, any types of terminals described belowcan operate as a base station by temporarily or semi-persistentlyperforming a function of the base station.

The user equipment according to the present disclosure can beimplemented as a mobile terminal (such as a smart phone, a panelpersonnel computer (PC), a notebook PC, an intelligent wearing device, aportable game terminal, a portable/dongle mobile router and a digitalcamera), an intelligent vehicle or a vehicle terminal (such as anautomobile navigation device). In addition, the user equipment may beimplemented as a terminal performing machine-to-machine (M2M)communication (referred to as a machine type communication (MTC)terminal). In addition, the user equipment may be a wirelesscommunication module (such as an integrated circuit module including asingle wafer) installed on each of the terminals described above.

Application examples of the base station and the user equipment aredescribed below with examples in conjunction with FIGS. 11 to 13.

In a specified scenario, the base station according to the presentdisclosure described above may be implemented by a macro base station ora small cell base station, and the macro base station and the small cellbase station may be implemented by eNBs shown in FIGS. 11 and 12.

FIG. 11 is a block diagram illustrating a first example of an schematicconfiguration of an eNB to which the technology according to the presentdisclosure may be applied. An eNB 1100 includes one or more antennas1110 and a base station device 1120. The base station device 1120 may beconnected to each of the antennas 1110 via an RF cable.

Each of the antennas 1110 includes a single or multiple antenna elements(for example, multiple antenna elements included in the multiple inputmultiple output (MIMO) antenna), and is used for the base station device1120 to transmit and receive wireless signals. As shown in FIG. 11, theeNB 1100 may include multiple antennas 1110. For example, the multipleantennas 1110 may be compatible with multiple frequency bands used bythe eNB 1100. Although FIG. 11 illustrates the example in which the eNB1100 includes multiple antennas 1110, the eNB 1100 may also include asingle antenna 1110.

The base station device 1120 includes a controller 1121, a memory 1122,a network interface 1123 and a wireless communication interface 1125.

The controller 1121 may be, for example, a CPU or DSP, and performsvarious functions of upper layers of the base station device 1120. Forexample, the controller 1121 generates a data packet from data insignals processed by the wireless communication interface 1125, andtransfers the generated packet via the network interface 1123. Thecontroller 1121 may bundle data from multiple baseband processors togenerate bundled data, and transfers the generated bundled data. Thecontroller 1121 may have logical function of performing control such asradio resource control, radio bearer control, mobility management,admission control and scheduling. The control may be performed incooperation with an eNB or a core network node in the vicinity.

The memory 1122 includes RAM and ROM, and stores the program that isperformed by the controller 1121 and various types of control data (suchas a terminal list, transmission power data and scheduling data).

The network interface 123 is a communication interface for connectingthe base station device 1120 to the core network 1124. The controller1121 may communication with a core network node or another eNB via thenetwork interface 1123. In this case, the eNB 1100 and the core networknode or other eNB may be connected to each other through a logicinterface (such as an S1 interface and an X2 interface). The networkinterface 1123 may also be a wired communication interface or a wirelesscommunication interface for wireless backhaul. If the network interface1123 is a wireless communication interface, the network interface 1123may use a higher frequency band for wireless communication than afrequency band used by the wireless communication interface 1125.

The wireless communication interface 1125 supports any cellularcommunication scheme (such as the long term evolution (LTE) and theLTE-Advanced), and provides wireless connection to a terminal located inthe cell of the eNB 1100 via the antenna 1110. The wirelesscommunication interface 1125 may typically include for example abaseband (BB) processor 1126 and an RF circuit 1127. The BB processor1126 may perform, for example, coding/decoding, modulating/demodulatingand multiplexing/de-multiplexing, and performs various types of signalprocessing of the layer (such as L1, media access control (MAC), radiolink control (RLC) and a packet data convergence protocol (PDCP)).Instead of the controller 1121, the BB processor 1126 may have a part orall of the above-described logical functions. The BB processor 1126 maybe a memory that stores the communication control program, or a modulethat includes a processor and related circuit configured to perform theprogram. Updating the program may allow the functions of the BBprocessor 1126 to be changed. The module may be a card or a blade thatis inserted into the slot of the base station device 1120.Alternatively, the module may be a chip that is mounted on the card orthe blade. Meanwhile, the RF circuit 1127 may include, for example, amixer, a filter and an amplifier, and transmit and receive wirelesssignals via the antenna 1110.

As shown in FIG. 11, the wireless communication interface 1125 mayinclude multiple BB processors 1126. For example, the multiple BBprocessors 1126 may be compatible with the multiple frequency bands usedby the eNB 1100. As shown in FIG. 11, the wireless communicationinterface 1125 may include multiple RF circuits 1127. For example, themultiple RF circuits 1127 may be compatible with multiple antennaelements. Although an example in which the wireless communicationinterface 1125 includes multiple BB processors 1126 and multiple RFcircuits 1127 is shown in FIG. 11, the wireless communication interface1125 may include a single BB processor 1126 or a single RF circuit 1127.

FIG. 12 is a block diagram illustrating a second example of anillustrative configuration of an eNB to which the technology accordingto the present disclosure is applied. An eNB 1200 includes one or moreantennas 1210, a base station device 1220 and an RRH 1230. The RRH 1230may be connected to each of the antennas 1210 via an RF cable. The basestation device 1220 and the RRH 1230 may be connected to each other viaa high-speed line such as an optical fiber cable.

Each of the antennas 1210 includes one or more antenna elements (such asthe multiple antenna elements included in the MIMO antenna), and is usedfor the RRH 1230 to transmit and receive the wireless signal. As show inFIG. 12, the eNB 1200 may include multiple antennas 1210. For example,the multiple antennas 1210 may be compatible with the multiple frequencybands used by the eNB 1200. The eNB 1200 may also include a singleantenna 1210 although FIG. 12 shows an example in which the eNB 1200includes multiple antennas 1210.

The base station device 1220 includes a controller 1221, a memory 1222,a network interface 1223, a wireless communication interface 1225 and aconnection interface 1227. The controller 1221, the memory 1222 and thenetwork interface 1223 are the same as the controller 1221, the memory1222 and the network interface 1223 described by referring to FIG. 12,and the network interface 1223 is configured to connect the base stationdevice 1220 to a core network 1224.

The wireless communication interface 1225 supports any cellularcommunication scheme (such as LTE and the LTE-Advanced), and provides awireless communication to a terminal located in a sector correspondingto the RRH 1230 via the RRH 1230 and the antenna 1210. The wirelesscommunication interface 1225 may typically include, for example, a BBprocessor 1226. The BB processor 1226 is the same as the BB processor1126 described by referring to FIG. 11, except that the BB processor1226 is connected to an RF circuit 1234 of the RRH 1230 via theconnection interface 1227. As shown in FIG. 12, the wirelesscommunication interface 1226 may include multiple BB processors 1226.For example, the multiple BB processors 1226 may be compatible withmultiple frequency bands used by the eNB 1200. Although FIG. 12 shows anexample that the wireless communication interface 1225 includes multipleBB processors 1226, the wireless communication interface 1225 mayinclude a single BB processor 1226.

The connection interface 1227 is an interface for connecting the basestation device 1220 (the wireless communication interface 1225) to theRRH 1230. Alternatively, the connection interface 1227 may be acommunication module for communication in the above-described high-speedline that connects the base station device 1220 (the wirelesscommunication interface 1225) to the RRH 1230.

The RRH 1230 includes a connection interface 1231 and a wirelesscommunication interface 1233.

The connection interface 1231 is an interface for connecting the RRH1230 (the wireless communication interface 1233) to the base stationdevice 1220. The connection interface 1231 may also be a communicationmodule for the communication in the above high-speed line.

The wireless communication interface 1233 transmits and receiveswireless signals via the antenna 1210. The wireless communicationinterface 1233 may typically include, for example, an RF circuit 1234.The RF circuit 1234 may include, for example, a mixer, a filter and anamplifier, and transmits and receives wireless signals via the antenna1210. As shown in FIG. 12, the wireless communication interface 1233 mayinclude multiple RF circuits 1234. For example, multiple RF circuits1234 may support multiple antenna elements. Although FIG. 12 shows anexample in which the wireless communication interface 1233 includesmultiple RF circuits 1234, the wireless communication interface 1233 mayinclude a single RF circuit 1234.

In the eNB 1100 and eNB 1200 shown in FIG. 11 and FIG. 12, thecommunication unit shown in FIG. 5 may be implemented by a combinationof the wireless communication interface 1125 of the eNB 1100 and theantenna 1110 or by the network interface 1123, or may be implemented bythe RRH 1230 of the eNB 1200 and the wireless communication interface1225 of the base station device 1220 via connection interfacestherebetween. For example, the identity group determining unit 401/501,secondary synchronization signal sequence generating unit 402/502 andinformation updating unit 504 can be implemented by the controller 1121or the controller 1221.

The communication devices according to the embodiments of the presentdisclosure described above can be implemented as a smart phone. Forexample, the smart phone may serve as a wifi access device by enabling awifi hotspot function. A wifi connection between the smart phone andother smart terminals uses unauthorized frequency spectrum resources.The smart phone is managed directly by, for example, a frequencyspectrum manger, to use the unauthorized frequency spectrum.

FIG. 13 is a block diagram illustrating an illustrative configuration ofa smart phone 1300 in which the technology according to the presentdisclosure may be applied. The smart phone 1300 may include a processor1301, a memory 1302, a storage device 1303, an external connectioninterface 1304, a camera 1306, a sensor 1307, a microphone 1308, aninput device 1309, a display device 1310, a speaker 1311, a wirelesscommunication interface 1312, one or more antenna switches 1315, one ormore antennas 1316, a bus 1317, a battery 1318 and an auxiliarycontroller 1319.

The processor 1301 may be, for example, a CPU or a system on chip (SoC),and controls functions of an application layer and another layer of thesmart phone 1300. The memory 1302 includes a RAM and a ROM, and stores aprogram executed by the processor 1301 and data. The storage device 1303may include a storage medium such as a semiconductor memory and a harddisk. The external connection interface 1304 is an interface connectingthe external device (such as a memory card and a universal serial bus(USB) device) to the smart phone 1300.

The camera 1306 includes an image sensor (such as a charge-coupleddevice (CCD) and a complementary metal oxide semiconductor (CMOS)), andgenerates a captured image. The sensor 1307 may include a group ofsensors such as a measurement sensor, a gyro sensor, a geomagneticsensor and an acceleration sensor. The microphone 1308 converts soundsinputted to the smart phone 1300 to audio signals. The input device 1309includes, for example, a touch sensor configured to detect touch onto ascreen of the display device 1310, a keypad, a keyboard, a button or aswitch and receives an operation and information inputted from the user.The display device 1310 includes a screen (such as a liquid crystaldisplay (LCD) and an organic light-emitting diode (OLED) display), anddisplays an output image of the smart phone 1300. The speaker 1311converts the audio signals outputted from the smart phone 1300 intosounds.

The wireless communication interface 1312 supports any cellularcommunication scheme (such as LTE and LTE-advanced), and performswireless communication. The wireless communication interface 1312 maytypically include, for example, a BB processor 1313 and an RF circuit1314. The BB processor 1313 may execute, for example, coding/decoding,modulating/demodulating and multiplexing/demultiplexing, and executevarious types of signal processing for wireless communication.Meanwhile, the RF circuit 1314 may include, for example, a mixer, afilter or an amplifier, and transmit and receive wireless signals viathe antenna 1316. The wireless communication interface 1312 may be achip module on which the BB processor 1313 and the RF circuit 1314 areintegrated. As shown in FIG. 13, the wireless communication interface1312 may include multiple BB processors 1313 and multiple RF circuits1314. Although FIG. 13 shows an example in which the wirelesscommunication interface 1312 includes multiple BB processors 1313 andmultiple RF circuits 1314, the wireless communication interface 1312 mayinclude a single BB processor 1313 and a single RF circuit 1314.

In addition to the cellular communication scheme, the wirelesscommunication interface 1312 may support another type of wirelesscommunication scheme, such as a short-distance wireless communicationscheme, a near field communication scheme and a wireless local areanetwork (LAN) scheme. In this case, the wireless communication interface1312 may include a BB processor 1313 and a RF circuit 1314 for eachwireless communication scheme.

Each of the antenna switches 1315 switches a connection destination ofthe antenna 1316 among multiple circuits (for example, circuits fordifferent wireless communication schemes) included in the wirelesscommunication interface 1312.

Each of the antennas 1316 includes one or more antenna elements (forexample, multiple antenna elements included in the MIMO antenna), and isused for the wireless communication interface 1312 to transmit andreceive wireless signals. As shown in FIG. 13, the smart phone 1300 mayinclude multiple antennas 1316. Although FIG. 13 shows an example inwhich the smart phone 1300 includes multiple antennas 1316, the smartphone 1300 may include a single antenna 1316.

In addition, the smart phone 1300 may include an antenna 1316 for eachwireless communication scheme. In this case, the antenna switch 1315 maybe omitted from the configuration of the smart phone 1300.

The bus 1317 connects the processor 1301, the memory 1302, the storagedevice 1303, the external connection interface 1304, the camera 1306,the sensor 1307, the microphone 1308, the input device 1309, the displaydevice 1310, the speaker 1311, the wireless communication interface 1312and the auxiliary controller 1319 with one another. The battery 1318supplies power to each block in the smart phone 1300 shown in FIG. 13via a feed line. The feed line is partially shown as a dash line in FIG.13. The auxiliary controller 1319, for example, operates a minimumnecessary function of the smart phone 1300, for example, in a sleepmode.

In the smart phone 1300 shown in FIG. 13, for example, the searchingunit 101/201, the synchronizing unit 102/202 and the detecting unit 203can be implemented by the processor 1301. In addition, the notifyingunit 204 and communication unit 701 can be implemented by the wirelesscommunication interface 1312 or a combination of the wirelesscommunication interface 1312 and the antenna 1316.

It can be understood that, the terms mentioned herein are only fordescribe certain embodiments, and are not intended to limit the presentdisclosure. “a” and “the” in a singular form used herein are intended toinclude a plural form, unless the context clearly indicates otherwise.It should be further known that, in the case that the word “include”used in the specification indicates that there are the mentionedfeatures, entirety, steps, operations, units and/or components, withoutexcluding that one or more other features, entirety, steps, operations,units and/or components or a combination thereof exist or are added.

In the aforementioned specification, the present disclosure is describedby referring to certain embodiments. However, it is understood by thoseskilled in the art that various modification and changes can be made tothe present disclosure without deviating from the scope of the presentdisclosure claimed by the claims.

The technology according to the present disclosure may be furtherimplemented with the following embodiments.

1. A device on a terminal side in a wireless communication system,including:

-   -   a searching unit configured to search for a target cell by means        of a synchronization signal sequence corresponding to a target        frequency range to be searched; and    -   a synchronizing unit configured to perform synchronization based        on a synchronization signal detected by the searching unit, so        as to synchronize the device with the target cell;    -   where in a case that the target frequency range falls within a        first frequency range, the searching unit searches for the        target cell by means of a synchronization signal sequence in a        first subset of a synchronization signal sequence set, the first        subset being a proper subset of the synchronization signal        sequence set.

2. The device on the terminal side according to solution 1, where thefirst frequency range is a range on unauthorized frequency band for thewireless communication system, and the target cell is a cell which isaccessed on unauthorized frequency spectrum.

3. The device on the terminal side according to solution 2, where thesynchronization signal sequence set is used when the device communicatesvia a carrier on authorized frequency band.

4. The device on the terminal side according to any one of solutions 1to 3, where the synchronization signal sequence is a secondarysynchronization signal sequence, and the searching unit is configured todecode a secondary synchronization signal of the target cell by means ofthe secondary synchronization signal sequence corresponding to thetarget frequency range.

5. The device on the terminal side according to any one of solutions 1to 4, further including: a communication interface configured to acquirea command for searching for the target cell and indication informationof the first subset through a first cell on the authorized frequencyband.

6. The device on the terminal side according to solution 5, where thecommunication interface receives upper-layer signaling comprising thecommand and the indication information through the first cell.

7. The device on the terminal side according to any one of solutions 1to 4, further including a communication interface configured to acquirean indication related to an updated synchronization signal sequencethrough the target cell after the device accesses to the target cell.

8. The device on the terminal side according to any one of solutions 1to 7, further including:

-   -   a detecting unit configured to detect whether an interference to        a reference signal received by the device in the first frequency        range is too large due to usage of the first subset; and    -   a notifying unit configured to notify a base station of the        target cell of a result of the detecting when it is detected        that the interference is too large.

9. The device on the terminal side according to solution 8, where

-   -   the synchronization signal sequence set includes a plurality of        proper subsets for cell search for the first frequency range,        and the searching unit detects an indication that the base        station of the target cell re-selects a second subset from the        plurality of proper subsets in response to the notification that        the interference is too large, and a synchronization signal        re-transmitted by the base station of the target cell, the        second subset being different from the first subset; and    -   the searching unit decodes the re-transmitted synchronization        signal by means of the second subset based on the indication.

10. The device on the terminal side according to any one of solutions 1to 9, where when the device performs long-term evolution assistedunauthorized frequency spectrum access, the searching unit uses asecondary synchronization signal of a cell where the device previouslyresides as the synchronization signal sequence to perform searching.

11. The device on the terminal side according to any one of solutions 1to 9, where if the device needs to perform inter-cell handover, thesearching unit acquires an indication related to the first subset basedon radio resource control configuration information from a base station.

12. The device on the terminal side according to solution 11, where thesynchronization signal sequence set includes a plurality of propersubsets for cell search for the first frequency range, and a sequencenumber of the first subset is included in the radio resource controlconfiguration information.

13. The device on the terminal side according to any one of solutions 1to 12, where in a case that the target cell cannot be searched out withall the sequences in the first subset, the searching unit searches byusing a sequence in a third subset which is one of the plurality ofproper subsets for the cell search for the first frequency range andwhich is different from the first subset.

14. A wireless communication method performed by a device on a terminalside, including:

-   -   searching for a target cell by means of a synchronization signal        sequence corresponding to a target frequency range to be        searched; and    -   performing synchronization based on a searched synchronization        signal so as to synchronize the device with the target cell;    -   where in a case that the target frequency range falls within a        first frequency range, the target cell is searched by means of a        synchronization signal sequence in a first subset of a        synchronization signal sequence set, the first subset being a        proper subset of the synchronization signal sequences set.

15. A device on a base station side in a wireless communication system,including:

-   -   an identity group determining unit configured to determine a        physical layer cell identity group for a target cell, where the        physical layer cell identity group is related to a frequency        range for the target cell; and    -   a secondary synchronization signal sequence generating unit        configured to generate a secondary synchronization signal        sequence for a secondary synchronization signal of the target        cell based on the physical layer cell identity group;    -   where in a case that the frequency range for the target cell        falls within a first frequency range, the physical layer cell        identity group is a first subset of a physical layer cell        identity group set, the first subset being a proper subset of        the physical layer cell identity group set.

16. The device on the base station side according to solution 15, wherethe first frequency range is a range on unauthorized frequency band forthe wireless communication system, and the target cell is a cell whichis accessed on unauthorized frequency spectrum.

17. The device on the base station side according to solution 16,further including a communication unit configured to transmit thesecondary synchronization signal on unauthorized frequency bandcorresponding to the target cell.

18. The device on the base station side according to solution 16,further including:

-   -   a communication unit configured to receive, from a terminal, a        notification that an interference to a reference signal received        by the terminal is too large due to usage of the first subset;    -   where in response to receiving the notification, the identity        group determining unit re-determines a second subset of the        physical layer cell identity group set as the physical layer        cell identity group, the second subset being a proper subset of        the physical layer cell identity group set and being different        from the first subset, and the secondary synchronization signal        sequence generating unit re-generates the secondary        synchronization signal sequence based on the second subset.

19. The device on the base station side according to solution 18,further including:

-   -   an information updating unit configured to generate system        broadcast information comprising indication information related        to the second subset and to be transmitted through the target        cell.

20. The device on the base station side according to solution 18,further including:

-   -   an information updating unit configured to generate system        broadcast information comprising indication information related        to the second subset and to be transmitted on authorized        frequency band.

21. The device on the base station side according to any one ofsolutions 18 to 20, where the communication unit is further configuredto notify another device on the base station side in the wirelesscommunication system of the indication information of the second subset.

22. The device on the base station side according to any one ofsolutions 15 to 21, where

-   -   the device on the base station side acquires a physical layer        cell identity group subset for a neighboring cell of the target        cell, and in a case that radio resource management involving the        neighboring cell is performed on a device on a terminal side in        current cell, the device on the base station side generates        radio resource control signaling to notify the device on the        terminal side of the cell identify group subset for the        neighboring cell.

23. The device on the base station side according to solution 18, wherethe communication unit is further configured to, in response toreceiving the notification, report an event that the interference is toolarge to a core network through an S1 interface and acquire informationrelated to an updated cell identity group from the core network.

24. A wireless communication method performed by a device on a basestation side, including:

determining a physical layer cell identity group for a target cell,where the physical layer cell identity group is related to a frequencyrange for the target cell; and

generating a secondary synchronization signal sequence for a secondarysynchronization signal of the target cell based on the physical layercell identity group;

-   -   where in a case that the frequency range for the target cell        falls within a first frequency range, the physical layer cell        identity group is a first subset of a physical layer cell        identity group set, the first subset being a proper subset of        the physical layer cell identity group set.

25. A wireless terminal device capable of communicating with a basestation on a first carrier, including:

-   -   a communication unit configured to receive a synchronization        signal transmitted from the base station on a second carrier        different from the first carrier; and    -   a synchronizing unit configured to match a secondary        synchronization signal in the synchronization signal with a        sequence in a first subset of a secondary synchronization signal        sequence set, to determine the secondary synchronization signal,        the first subset being a proper subset of the secondary        synchronization signal sequence set.

26. A base station in a wireless communication system, where the basestation is capable of communicating with a wireless communicationterminal on a first carrier, and the base station includes:

-   -   a communication unit configured to transmit a synchronization        signal comprising a secondary synchronization signal on a second        carrier different from the first carrier;    -   where the secondary synchronization signal is selected from a        first subset of a secondary synchronization signal sequence set,        the first subset being a proper subset of the secondary        synchronization signal sequence set.

The invention claimed is:
 1. A device on a terminal side in a wirelesscommunication system, comprising: circuitry configured to perform firstwireless communication with a LTE cell of a licensed band; search for atarget cell that operates at a frequency range in an unauthorizedfrequency band for the terminal side, the target cell being a cell whichis accessed in an unauthorized frequency spectrum; perform a secondwireless communication with the LTE cell of the licensed band; detectwhether an interference signal is present on a reference signal receivedby the device in the frequency range for a time duration exceeding apredetermined time threshold; and in response to detecting a presence ofinterference, notify a base station of the target cell of a result ofthe detection of interference, wherein, the first wireless communicationand the second wireless communication perform are performed usingcarrier aggregation.
 2. The device on the terminal side according toclaim 1, wherein, communications with the target cell are based on asynchronization signal sequence corresponding to a target frequencyrange to be searched.
 3. The device on the terminal side according toclaim 2, wherein, downlink synchronization signals include primarysynchronization signals (PSS) and secondary synchronization signals(SSS), and different physical layer cell identities (PCI's) are definedby combinations of the primary synchronization signals and the secondarysynchronization signals.
 4. The device on the terminal side according toclaim 3, wherein the circuitry is further configured to receive asecondary synchronization signal sequence for a secondarysynchronization signal of the target cell based on a physical layer cellidentity group.
 5. The device on the terminal side according to claim 1,wherein the interference signal is detected by a signal of referencesignal received quality (RSRQ).
 6. A method of operating a device on aterminal side in a wireless communication system, comprising: performingfirst wireless communication with a LTE cell of a licensed band;searching for a target cell that operates at a frequency range in anunauthorized frequency band for the terminal side, the target cell beinga cell which is accessed in an unauthorized frequency spectrum;performing second wireless communication with the LTE cell of thelicensed band; detecting whether an interference signal is present on areference signal received by the device in the frequency range for atime duration exceeding a predetermined time threshold; and in responseto detecting a presence of interference, notifying a base station of thetarget cell of a result of the detection of interference, wherein, thefirst wireless communication and the second wireless communicationperform are performed using carrier aggregation.
 7. The method accordingto claim 6, wherein, communications with the target cell are based on asynchronization signal sequence corresponding to a target frequencyrange to be searched.
 8. The method according to claim 7, wherein,downlink synchronization signals include primary synchronization signals(PSS) and secondary synchronization signals (SSS), and differentphysical layer cell identities (PCIs) are defined by combinations of theprimary synchronization signals and the secondary synchronizationsignals.
 9. The method according to claim 8, further comprisingreceiving a secondary synchronization signal sequence for a secondarysynchronization signal of the target cell based on a physical layer cellidentity group.
 10. The method according to claim 6, wherein, theinterference signal is detected by a signal of reference signal receivedquality (RSRQ).